Internal Parasites Flashcards
Phyla: Sarcomastigophora
Protozoans. Example: Giardia spp, Toxiplasma gondii and Eimeria spp.
Phyla: Nemathelminthes
Roundworms. Class Nematoda
Phyla: Platyhelminthes
Flatworms example: Class Tremetoda flukes and Class Cestoda tapeworm.
Phyla: Acanthrocephala
Thorny-headed worms
Class Nematoda
Superfamilies: Ascaridoidea/Ascarids, Oxyuroidea/pinworms, Metastrongyloidea/ lungworms, Trichostrongyloidea, Rhabditoidea, Strongyloidea, Filarioidea, Trichuroidea.
superfamily: Ascaridoidea
Ascarids-Large roundworms.
Toxocara canis & felis, Parascaris equorum, Ascaris suum, Heterakis gallinarum
Common roundworms (aka Ascarids)
Toxocara canis (dogs) Toxocara cati (cats) Toxascaris leonina (cats and dogs) Parascaris equorum (equine) Ascaris suum (pigs) Heterakis gallinarum (poultry) Ascaridia galli (poultry) Baylisascaris procyonis (raccoons)
Common lungworms (superfamilies Trichostrongyloidea, Metastrongyloidea, Trichuroidea)
Dictyocaulus viviparous (cattle and deer) Dictyocaulus filaria (sheep) Dictyocaulus arnfieldi (donkeys, horses) Protostrongylus stilesi (big horned sheep) Protostrongylus ruschi (big horned sheep) Protostrongylus rufescens (sheep and goats) Muellerius capillaris (sheep and goats) Aelurostrongylus abstrusus (cats) Metastrongylus apri (pigs) Filaroides osleri (dogs) Capillaria aerophila (foxes, occasionally dogs and cats)
Common threadworms (Rhabditoidea)
Strongyloides stercoralis (canine, also cats, foxes, humans, other primates) Strongyloides westeri (horses- usually foals 2 weeks- 6 months)
Common hookworms (Strongyloidea)
Ancylostoma caninum (dogs, wild canids, raccoons and badgers) Ancylostoma braziliense (cats and dogs) Ancylostoma tubaeformae (cats and wild felines) Unicineria stenocephala (dogs and wild canids)
Strongyles (superfamily Strongyloidea)
- 2 groups- small strongyles and large strongyles.
- mixed infections are common.
- direct life cycles
- common clinical signs: anaemia, diarrhea, ill-thrift
- prolific egg producers
- most frequently clinical problems occur in the spring due to activation and emergence of large numbers of dormant migrating larvae
- it can be assumed that all grazing horses are infected to some degree
Large Strongyles (superfamily Strongyloidea)
-Strongyles equinus
-Strongyles edentatus
-Strongyles vulgaris***
-direct life cycles
-complicated migration pattern: 1st stage larvae develop in ova, hatch, become free-living 2nd and 3rd stage larvae. Once 3rd stage larvae penetrate caecal mucosa they migrate to various areas of the body.
S. edentates and S. equines leave caecum sand migrate to the peritoneum and liver, ultimately returning to the caecum
S. vulgarism leaves the caecum and migrates extensively through the cranial mesenteric artery and its branches before returning to the caecum. The resulting venomous thrombosis and arteritis may result in obstruction and occlusion of the cranial mesenteric artery which supplies the intestinal tract.
Trichostrongyles (superfamily Trichostrongyloidea)
Haemonchus contortus (cattle, sheep, goats and llamas)
Ostertagia ostertagi (cattle, sheep, goats and llamas)
Trichostrongylus axei (horses, cattle, sheep, goats and llamas)
Cooperia spp (cattle, sheep, goats and llamas)
Nematodirus spp (cattle, sheep, goats and llamas)
-simple, direct life cycle
-mucosal migration only
-zoonotic (fecal ingestion)
-are capable of hypobiosis during periods of environmental stress
-typical strongyle ova (except Nematodirus), so impossible to identify genus and species by fecal floatation alone.
-control: pasture rotation and regular deworming.
Ostertagiasis
-refers to and infestation of Ostertagia spp.
-3 stages/types of infestation:
type 1: larvae mature and reproduce
pre-type 2: no clinical signs. 4th stage larvae in the abomasum are inhibited in gastric glands and accumulate over winter (hypobiosis)
type 2: inhibited larvae mature at the same time, resulting in increases on abomasal pH and mucous production. Severe diarrhea and dehydration result.
Blood parasites (Superfamily Filariodea)
Dirofilaria immitis (dogs, cats, human) Dipetalonema reconditum (dogs) -both are found in the circulating blood